While viewing digital videos, hereinafter referred to simply as videos, users often wish to preview various portions of the videos. For example, when viewing a five-minute video, a user may wish to determine content of the video at a four-minute mark. In order to preview content within videos, a computing device often presents a video progress bar which enables the users to provide inputs to the computing device to preview and navigate to seek points corresponding to time positions within the video. For example, the computing device may receive an input corresponding to a cursor hover over a specified seek point in the video progress bar and cause a display of a video frame corresponding to the seek point. In typical videos, a simple display of a video frame of the video associated with a seek point works well. However, basic video frame display for panoramic videos can be problematic due to the amount of content included within the video frame for display by the computing device.
Panoramic videos are typically output as 3D projections by the computing device due to fields of view that are generally larger than that of a human eye. 3D projections enable a user to “look around” and give a sense of actually being in the scene when rendered by the computing device. Typically, this is performed by the computing device through output of a viewport that contains a smaller field of view that can be manipulated in order to view other portions of the scene, e.g., look up, down, sideways, etc. Thus, at any given time, a user is generally able to view a limited portion of the panoramic video that is output by the computing device. Because of the large fields of view of panoramic videos, meaningful seek previews become difficult.
Conventional seek preview techniques fail to effectively convey an entire video frame when confronted with panoramic videos either due to attempting to display the entire frame as a static image or by merely displaying a limited portion of the frame. For example, in one conventional technique, a computing device displays an entire 2D projection of a frame of a panoramic video corresponding to the seek point. However, by doing so, the resultant preview contains distortions to objects that often result in an inability to discern individual objects within the projection. In another conventional technique, a computing device may display a portion of the frame at the seek point corresponding to a current viewport. Although the portion of the frame is visually pleasing and comprehendible to a user, many of the objects within the image may reside outside of the viewport. Accordingly, if the video involves an object that is outside of the viewport at the seek point, the user may miss key details of the video at the seek point and determine that the seek point has nothing of interest. Thus, conventional techniques fail to generate useful seek previews for panoramic videos such that a user can easily comprehend content within a frame of the panoramic videos corresponding to seek points.